Process of obtaining pure copper.



UNITED LUGIEN JUMAU, Oi" PARIS, FRANCE.

PROCESS OF OBTAINING PURE COPPER.

Specification of Letters Patent.

Patented Nov. 12, 1907.

Application filed July 19. 1906. Berial No. 326.844.

To all whom it may concern:

Be it known that I, LUCIEN JUMAU, a citizen of France, residing atParis, in the said Republic, have invented new and useful Improvementsin Process for Obtaining Pure Copper, of which the following is aspecification.

My invention relates to an improved process for obtaining pure metalliccopper from a solution of a salt of copper, and it consists in the stepsand processes herein described and claimed.

In the usual wet method of extracting copper from its ores, the ore,with or without previous roasting, is leached with a suitable solutionfor dissolving the copper; the copper being usually extracted in theform of a sulfate. The copper solution thus obtained contains manyimpurities, which render it diiiicult to obtain the copper in a pureform therefrom. A well known process consists in precipitating thecopper from the solution by triaating the latter with scrap iron; the

co er bein reci itated as cement co) or which contains impuritiesnecessitating subsequent treatment by a dry method for refining thecopper.

The object of my invention is to eliminate the treatment with iron whichis long and costly and to precipitatethe copper in a pure state from itssolution.

By my improved process, the salt of copper is heated under pressure inthe presence of a suitable suliite, such as, for example, sulfitc ofammonia, orsuliite of hydrogen, commercially known as sulfurous acid. Inthis process, the copper is precipitated from the solution in the formof pure metallic copper, and the sullite is oxidized to a sulfate. Thus,a suliite of ammonia would be oxidized to sulfate of ammonia, andsuliite of hydrogen would be oxidized to sulfate of hydrogen,commercially known as sulfuric acid.

As a practical example of the carrying out of my process, a solution ofsulfate of copper obtained by leaching ores in the usual manner issubjected to the action of heat and pressure in the presence of asuitable proportion of suliite of hydrogen; the process beingconveniently performed in a digester lined with lead. The action isfound to be ,very rapid, and it is found that the proportion of copperprecipitated in a pure metallic form is increased by raising thetemperature, the increase varying approximately as the temperature; atemperature of 170 C. has proven very satisfactory in practice.

In order to operate at a relatively high temperature without engendcringan excessive pressure, it has proven desirable to employ only thenecessary theoretically determined proportion of suliite of h yd rogcn,and to gradually increase the heat to the desired temperature. Whensuliite of hydrogen is employed as the re ducing agent, the finaloperation, omitting certain intermed iate reactions, may be stated asfollows:

The copper obtained by this process is absolutely pure and free fromsulfite or oxid of copper.

If the solution of the salt of copper contains precious metals, they canbe separated by a preliminary treatment of such solutionwith suliite ofhydrogen under the action of heat and at ordinary pressure. Thispreliminary treatment precipitates the precious metals without affectingthe copper in the solution. If a sufficient quantity of suliite ofhydrogen remains in the solution after removal of the precipitatedprecious metals, the copper can then be precipitated in a pure metallicform by increasing the pressure. However,

my preferred method is to add to the solution after the removal of theprecipitated precious metals, a suiiicopper. The copper precipitate maybe fused, or compressed into briquets by hydraulic pressure, and suchbriquets may then be employed as anodes if it is desired to furtherrefine the copper by electrolytic process.

From the above description, it will be understood that my improvedprocess is especially advantageous in the treatment of suliid ores; thesuliitc of hydrogen employed being obtained during the roasting of suchores, and the sulfuric acid resulting from the final treatment beingemployed for leaching a fresh supply of ores.

I have illustrated a preferred and satisfactory process, but, obviously,changes could be made within the spirit and scope of my invention.

Having thus described my invention, what I claim as new therein anddesire to secure by Letters Patent 1. The herein described process forobtaining pure copper. which consists in precipitating ihe preciousmetals from :1 solution of u suit of copper by treating said solutionwith u suliiie at u raised lempcruture under substantially atmosphericpressure, separating the solution from the precious metals thusprecipitated, and subjecting said sepnrulcd soiuiion to heat andpressure in the presence of u snliite.

L. The herein described process for obtaining pure copper, whichconsists in precipitating the precious metals from a solution of a suitof copper by treating said solution with n suiiite ut a raisedtemperature under substantiuiiy atmospheric pressure, separating thesolution from the precious lnetnls thus precipitated, treating saidseparuied solution with a suillte, and subjecting said solution andsuiiiie to heat and pressure for precipitating metallic coppcl.

35. The herein described process for obtaining pure copper, whichconsists in precipitating the precious metals from a solution of a suitof copper by treating said solution with a sulflte at a raisedtemperature under substantially atmospheric pressure, separating thesolution from the precious metals thus precipitated, treating saidseparated solution with a sulfite, subjecting said solution and sulfiteto heat and pressure for precipitating metallic copper, and transformingthe copper thus precipitated into pure massive copper.

4. The herein described process for obtaining pure copper, whichconsists in precipitating the precious metals from a solution of a saltof copper by treating said solution with sulfite of hydrogen at a raisedtemperature under substantially atmospheric pressure, separating thesolution from the precious metals thus precipitated, treating saidseparated solution with sulfite of hydrogen, and subjecting saidsolution and sulfite of hydrogen to heat and pressure for precipitatingmetallic copper.

5. The herein described process for obtaining pure copper, whichconsists in precipitating the precious metals from a solution of a saltof copper by treating said solution with a sulfite at a temperature ofapproximately 170 C. under substantially atmospheric pressure,separating the solution from the precious metals thus precipitated,treating said separated solution with a sulfite, subjecting saidsolution and sulfite to heat and pressure for precipitating metalliccopper, and transforming the copper thus precipitated into pure massivecopper.

In testimony whereof I have signed my name tothis specification in thepresence of two subscribing witnesses.

, LUCIEN JUMAU.

Witnesses JuLns FAYOLLET, EUGENE PICHON.

